Tuesday, 28 February 2012

Rainfall record

I shall add to this as the next few days unfold, but we have just gone past the highest monthly rainfall I have recorded in the 5 years we have been living here.  That is 162.5mm in the first 28 days of February 2012: the previous record was 158.3mm in February 2010.

Here is the radar immediately after the record fell:
Clearly there is more on the way, in the short term, and by the time I went to bed (10pm) another 10mm had fallen.

In the medium term the Bureau of Meteorology (BoM) is forecasting - through a computer model with no forecaster intervention - another 25 - 50mm on Wednesday.  That is, tomorrow.

The day after Wednesday is Thursday.  Here is what they have in mind - or rather in computer - for that day.
That blue blob represents 100mm -150mm.  That is roughly between 25 and 33% of the total rainfall of 2009 in one day!

So we made it through the Tuesday night, scoring another 10mm of steady light rain through the night.   That has got us up to 186mm for the month, and with it being a Leap Year  we still have a day to go.  I have just looked at the BoM 4 day cumulative rainfall forecast.  I suggest click on the image to get a bigger version.
Canberra is in the Deep Purple blob, so the BoM computer is expecting 200-300mm of rain over the next 4 days: basically it isn't going to stop.  The Flood Watch announcement from BoM said the worst rain was going to be in the catchment around Goulburn (the light purple blob suggesting >300mm).  As recently as 2 years ago Goulburn had effectively run out of water and the prospect of trucking in all water to the town was being floated (sorry about that).   I suspect that if the forecast falls happen the problem will become one of getting trucks into the town - although I can't see the Hume Highway getting cut by floods between Goulburn and Sydney.

By the end of the month (for this purpose that was 10pm Wednesday)  we had received 198mm and it was raining steadily.

So March has started.  It rained more or less through the night: when daylight (or what looks likely to pass for daylight) arrives I will go and check the gauge, expecting to find at least 30mm in there.  Here is the 128km radar image for 6am.
A little later I went down to the Creek crossing to see what was there.  Lotsa water was there.

Fortunately the 512km image is a tad more optimistic as we are close to the Northern edge of the band and it is moving in the usual NW-> SE direction.
Then I checked the 28 day long range forecast on the Elders site.
 I cannot remember ever seeing every day in a month coloured green.  Certainly I have never seen 21/28 days forecast as high chance of rainfall.

2 comments:

Denis Wilson said...

Sounds like Goulburn and Cooma both copped it.
It annoys me that Sydney media regard any flow at all over the Warragamba Dam outflow as "wasted".
That's a river there - and its meant to have a flow.
Alan Stephenson is crowing - he got more rain in Nowra than I did in Robbo.
Denis

Flabmeister said...

If it was Canberra there would be an immediate clamour from the destruction industry - sorry, they call themselves 'construction' don't they - to whack a few more metres on the wall and stop all of that.

And if the labour Party is power they will see this is a Good Thing for the CFMEU and make it so.

Of course if the Liberals are in power the situation would be completely different. They would see it as a Good Thing for the members of the Canberra Club who own destruction - sorry can't help myself - companies and make it so.

If the Greens were in power they would establish a workshop into how to tell if the rain has stopped.